An African species of Pentatomidae, Agonoscelis puberula Stål, is reported for the first time from Mexico, the southern United States and the islands of Jamaica and Hispaniola, where it has now established. The oldest Western Hemisphere record dates from 1985. This species has gone unrecognized probably because of its close resemblance to species of the New World genus Trichopepla Stål. The primary host plant of A. puberula is the introduced weed, common horehound, Marrubium vulgare L. It has also been reported damaging winter fruits in South Africa.
In this paper we give the first report of the African pentatomid bug, Agonoscelis puberula Stål, in the New World. Established populations of this stink bug have been discovered in the United States, Mexico, and the islands of Jamaica and Hispaniola. The species was first found among a series of specimens collected in 1991 near the town of Yautla in the state of Morelos, Mexico. These specimens were tentatively identified by one of us (GOL) as an undescribed species of the north-temperate genus Trichopepla Stål, to which they keyed in Rolston and McDonald’s (1984) treatment of Western Hemisphere Pentatomini. Its discovery in the Greater Antilles led another of us (JEE) to recognize this stink bug as an introduced species of the genus Agonoscelis Spinola, one referred to in the economic literature as a “cluster bug” (Haines 1935).
Taxonomy and Recognition
As in Trichopepla, species of Agonoscelis are generally yellowish, often with a red tinge and with black punctures arranged in a pattern of irregular dark stripes, and a distinctly hirsute dorsum (Fig. 1). Other shared characteristics include the scent gland orifice attended by a short auricle; the post-frenal scutellum more than half the width of the scutellar base, and base of the abdomen lacking a tubercle. In both genera the head is elongate compared with other pentatomines. Our specimens range from 8-10 mm in body length. In spite of their similarity, Trichopepla and Agonoscelis have been split into different tribes. This anomaly arises largely because there is no consensus classification for the Pentatominae. American workers, such as Rolston & McDonald (1984), follow the tribal arrangement in Kirkaldy’s Catalogue (1909) which places both genera in the Pentatomini. Asian workers, such as Ahmad et al. (1974), follow the arrangement of Distant (1921) which places Agonoscelis in the Eurydemini (=Strachiini). African workers, such as Cachan (1952), include Agonoscelis with the tribe Carpocorini. Inasmuch as there are no external morphological characters to distinguish Agonoscelis from Trichopepla, their placement in different tribes is problematic. According to McDonald (1966), the female spermatheca of Trichopepla is unique in lacking a sclerotized supporting rod and pumping region that is present in all other Pentatomines, including Agonoscelis (illustrated by Gross 1976). Such being the case, the separation of the two genera can be sustained, although the tribal-level separation seems dubious. Agonoscelis puberula has a distinctively marked hemelytral membrane featuring dark radiating stripes. This character is variable among species of Agonoscelis, but the membrane is unmarked in all species of Trichopepla (McDonald 1976); thus, the striped membrane allows quick recognition of this adventive stink bug.
The genus Agonoscelis has not been revised, although regional faunal treatments (Horváth 1904; Jensen-Haarup 1920; Cachan 1952; Yang 1962; Ahmad et al. 1974; Linnavuori 1975; Linnavuori 1982; Hsaio et al. 1977) provide means to diagnose many of the species. There are 22 nominal species of Agonoscelis including those of uncertain validity. Among the determined specimens available to us for study, representing six species, we noted that the male genitalia are distinctive to a given species, and it is on these characters that our determination relies. The New World invader is conspecific with specimens from South Africa identified by D. A. Rider and others as A. puberula Stål. The male genitalia of this particular species are illustrated by Linnavuori (1975) whose material was compared to Stål’s types in Stockholm. We have deposited voucher specimens in the United States National Museum, the Canadian National Collection, the Instituto de Biologia of the Universidad Nacional Autonoma de México, at Texas A&M University, in the Florida State Collection of Arthropods, and in the collections of the authors.
Agonoscelis puberula is native to southern and eastern Africa extending northward to the Arabian peninsula (Linnavuori 1982). Our oldest New World record dates from 1985 on the island of Jamaica. The first records for the United States are from Arizona in 1990. U.S. records include Arizona, New Mexico, and Texas. It is also well established in Mexico with records from Yucatan in the south to Nuevo Leon in the north covering the years 1988 to 2001. Our collection data includes the following specific localities and dates:
JAMAICA: St. Andrew Parish, 2 mi. S. Newcastle, 2-VIII-1985, C.B. & H.V. Weems Jr. & G.B. Edwards.
DOMINICAN REPUBLIC: La Vega: 21 Km S Jarabacoa, 18-26-VI-1994, C. & K. Messenger.
MEXICO: Guanajuato: San Miguel de Allende, 7-11-VIII-1988, G. B. Edwards; Chipicuaro, Presa Solis, 12-III-1997, E. Barrera & H. Brailovsky; Ojo Seco, 12-III-1997, E. Barrera & H. Brailovsky; San Antonio Emenguaro, 12-III-1997, H. Brailovsky, E. Barrera & G. Ortega-Leon. Morelos: Yautla, 3-V-1991, H. Brailovsky & E. Barrera. Distrito Federal: Piramides de Cuicuilco, 2-IV-1992, E. Gonzalez; Delegacion Iztapalapa, 1-VIII-1999, J. Contreras; Colonia Irrigacion, 18-VI-2001, H. Brailovsky. Mexico: Ixtapan de la Sal, 4-X-2000, H. Brailovsky & E. Barrera; Malinalco, VII-1996, E. Barrera. Guerrero: Tuxpan, 25-X-2001, H. Brailovsky, E. Barrera & G. Ortega-Leon. Hidalgo: Huichapan, 5-VI-1999, H. Brailovsky & E. Barrera; Huasca, 4-VIII-1995, H. Brailovsky. Michoacan: San Lorenzo, 24-X-2001, H. Brailovsky & E. Barrera. Oaxaca: Dominguillo, 18-II-1998, H. Brailovsky, E. Barrera & G. Ortega-Leon; Tehuacan-Oaxaca Km 140, 11-III-2000, H. Brailovsky & E. Barrera. Puebla: Tecamachalco-Tehuacan Km 1, 12-VI-1993, H. Brailovsky & E. Barrera; La Trinidad, 3-II-1994, E. Barrera & G. Ortega-Leon; La Trinidad, 13-II-1994, E. Barrera & G. Ortega-Leon; La Trinidad, 21-III-1994, E. Barrera & G. Ortega-Leon; Atlixco 23-IV-1994, E. Barrera & G. Ortega-Leon; Atlixco-La Trinidad, 29-V-1994, H. Brailovsky & E. Barrera; La Trinidad, 15-VI-1994, E. Barrera & G. Ortega-Leon; 5 Km SE Atlixco, 23-IV-1994, 15-VI-1994, H. Brailovsky, E. Barrera & G. Ortega-Leon; 2 Km W. La Trinidad, 19-III- 1994, G. Ortega-Leon & E. Barrera; Atexcal, 11-III-1994, E. Barrera & G. Ortega-Leon; Nicolas Bravo, 20-III-1993, H. Brailovsky, E. Barrera & G. Ortega-Leon; Tecamachalco, 6-I-1993, 27-I-1993, 12-VI-1992, 20-VII-1992, H. Brailovsky & E. Barrera; Atlixco, 18-VIII-1996, H. Brailovsky, E. Barrera & G. Ortega-Leon; Portezuelo, 10-II-1995, E. Barrera & G. Ortega-Leon. Queretaro: Pinal de Amoles, 27-IV-1998, 1-III-1998, E. Barrera & G. Ortega-Leon. Yucatan: Temax, 24-V-1995, E. Barrera & H. Brailovsky. Nuevo Leon: El Pinito, 3-IX-1995, D.B. Thomas & J. Burne.
UNITED STATES: Arizona: Pinal Co., Peppersauce Canyon, Santa Catalina Mtns., 9-IV-1991, C. Olson; Santa Cruz Co., Madera Canyon, 16-IV-1990, 17-VII-1990, 27-VII-1990, W. Jones; Patagonia, 8-VII-1994, B. Brown & E. Wilk; Santa Rita Mtns., Florida Canyon, 1-VIII-1992, W. Jones; Arrivaca Springs 1-VIII-1992, W. Jones. New Mexico: Hidalgo Co., 11 mi. NE Lordsburg, 31-VIII-2000, J. Huether. Texas: Concho Co., Eden, 29-XII-1999 [no collector].
At four separate Arizona localities a total of 26 adults was collected by one of us (WJ) on the pandemic weed, common horehound, Marrubium vulgare L. (Labiatae). At one of these sites nymphs were also present. This is also a known host plant for the Australian horehound bug, Agonoscelis rutila (F.) (Gross 1976). In South Africa, Haines (1935) reported that A. puberula breeds on its natural host plant in the summer, but overwinters in buildings and on fruit trees, sometimes clustering on the fruits and causing “considerable damage.” Unfortunately, Haines neglected to state the species of the host plant or the fruit damaged in South Africa. Our specimens from Concho County, Texas, were found on December 29 among stems and leaves of live oak, suggesting that they were overwintering in this habitat.
Our colleague Thomas J. Henry (USDA-ARS) informs us that he has frequently identified Agonoscelis versicolor (F.), intercepted on cut flowers shipped to the United States from South Africa via the Netherlands. This suggests a plausible route for the entry of A. puberula which may have established because of the ready availability of an acceptable host plant. According to Correll and Johnston (1970), common horehound is widely distributed in North America, flowers throughout the year, and is a weed typical of waste places and roadsides.
The authors are grateful to Thomas J. Henry, Systematic Entomology Laboratory, USDA-ARS, Washington D.C. for the loan of determined specimens of Agonoscelis in the National Museum of Natural History, Smithsonian Institution, Washington D.C., and information on intercepted stink bugs. We also extend thanks to the curators of the following institutions for access to material in their collections: Carl Olson, University of Arizona, Tucson; Edward G. Riley, Texas A&M University, College Station; Susan Halbert, Florida State Collection of Arthropods, Gainesville; and, Michael D. Schwartz, Canadian National Collection, Ottawa. Chris Mari Van Dyck produced the photograph in Figure 1 and Rene Davis enhanced the photo with Adobe Photoshop.